Fragrance compounds

ABSTRACT

Novel compounds having the structure (I) where R=methyl, ethyl or propyl, R 1 =methyl or H, R 2 =methyl, ethyl or propyl, R 3 =methyl or H, R 4 =methyl or ethyl, R 5 ═H or methyl, and where R 3  and R 5  are not both H, excluding N-ethyl-2-methyl-N-(3-methylphenyl) propanamide, can have desirable odour properties, typically of a tropical fruit, cassis character and find use in perfumes and perfumed products

FIELD OF THE INVENTION

This invention concerns novel fragrance compounds, and perfumes andperfumed products comprising the novel compounds.

BACKGROUND TO THE INVENTION

Siddall T. H. et al, Journal of the American Chemical Society, 1966,88(6), p1172–1176 describes the preparation, and more particularly theanalysis by proton magnetic resonance (pmr) spectroscopy, of a number ofN,N-disubstituted amides.

The present invention concerns novel N,N-disubstituted amides,particularly those amides possessing desirable fragrance properties.

SUMMARY OF THE INVENTION

In one aspect the present invention provides a compound having thestructure

where R=methyl, ethyl or propyl, R₁=methyl or H, R₂=methyl, ethyl orpropyl, R₃=methyl or H, R₄=methyl or ethyl, R₅=H or methyl, and where R₃and R₅ are not both H, excludingN-ethyl-2-methyl-N-(3-methylphenyl)propanamide.

For brevity and simplicity, such materials will be referred to as “theamide”, “the novel amide” or “the amide of the invention”.

The amides of the invention can possess fragrance or odour propertieswhich are generally regarded as interesting, pleasant or attractive,typically having fruity, cassis odour properties.

The currently preferred amide in accordance with the invention hasR=ethyl, R₁=H, R₂=ethyl, R₃=methyl, R₄=methyl and R₅=H. This compoundthus has the structure

and is 2-ethyl-N-methyl-N-(3-methylphenyl)butanamide. For brevity andsimplicity this amide is referred to herein as compound 1. Compound 1has desirable odour properties, generally described as tropical fruit,cassis. Compound 1 has a wide range of chemical stability and so findspotential use in a wide range of products. Compound 1 also has excellentinsect repellency properties, equivalent to those ofN-N-diethyl-m-toluamide (DET). Furthermore, compound 1 has good clothand hair substantivity properties, having good substantivity on wetcloth and moderate substantivity on dry cloth.

Compound 1 might be considered to have some structural similarities tothe following known fragrance molecules:

Molecule A is known by the Trade Mark Gardamide and has grapefruit,rhubarb odour properties. Molecule B (described in WO 96/30470 of Quest)is known by the Trade Mark Agarbois and has precious wood odourproperties. It should thus be noted that the odour profile of compound 1(tropical fruit, cassis) is very different from those of molecules A andB, in a way that is not predictable. Further, compound 1 is far superiorto molecules A and B in terms of additional benefits such as bettersubstantivity properties (both wet and dry cloth substantivity ofcompound 1 are better than that of molecules A and B). Moreover, theinsect repellent properties of compound 1 are superior to those ofmolecules A and B.

Further, amides in accordance with the present invention, andparticularly compound 1, might also be considered to have somestructural similarities to the molecule,N-phenyl-N-methyl-2-ethylbutyric acid amide which is described in U.S.Pat. No. 3,909,462 as being useful in perfumery on the basis of itsherby note. The molecule is also described as possessing a grapefruitaroma. Both of the odour/aroma descriptors given for this molecule aredifferent to the odour properties of compound 1.

A further amide exemplifying the invention has R=methyl, R₁=H,R₂=propyl, R₃=methyl, R₄=methyl and R₅=H. This compound thus has thestructure:

and is N, 2-dimethyl-N-(3-methylphenyl)pentanamide. This amide hasfruity, cassis, citrus odour properties.

The odour properties of the amides of the invention mean that an amideor mixture of amides in accordance with the invention may be used assuch to impart, strengthen or improve the odour of a wide variety ofproducts, or may be used as a component of a perfume (or fragrancecomposition) to contribute its odour character to the overall odour ofsuch perfume. For the purposes of this invention a perfume is intendedto mean a mixture of fragrance materials, if desired mixed with ordissolved in a suitable solvent or mixed with a solid substrate, whichis used to impart a desired odour to the skin and/or product for whichan agreeable odour is indispensable or desirable. Examples of suchproducts are: fabric washing powders, washing liquids, fabric softenersand other fabric care products; detergents and household cleaning,scouring and disinfection products; air fresheners, room sprays andpomanders; soaps, bath and shower gels, shampoos, hair conditioners andother personal cleansing products; cosmetics such as creams, ointments,toilet waters, preshave, aftershave, skin and other lotions, talcumpowders, body deodorants and antiperspirants, etc. As noted above,amides in accordance with the invention can show good substantivity tohair and cloth, both wet and dry, and hence have good potential for usein fabric treatment products and hair care products.

Other fragrance materials which can be advantageously combined with oneor more amides according to the invention in a perfume are, for example,natural products such as extracts, essential oils, absolutes, resinoids,resins, concretes etc., but also synthetic materials such ashydrocarbons, alcohols, aldehydes, ketones, ethers, acids, esters,acetals, ketals, nitrites, etc., including saturated and unsaturatedcompounds, aliphatic, carbocyclic, and heterocyclic compounds.

Such fragrance materials are mentioned, for example, in S. Arctander,Perfume and Flavor Chemicals (Montclair, N.J., 1969), in S. Arctander,Perfume and Flavor Materials of Natural Origin (Elizabeth, N.J., 1960)and in “Flavor and Fragrance Materials—1991”, Allured Publishing Co.Wheaton, Ill. USA.

Examples of fragrance materials which can be used in combination withone or more amides according to the invention are: geraniol, geranylacetate, linalol, linalyl acetate, tetrahydrolinalol, citronellol,citronellyl acetate, dihydromyrcenol, dihydromyrcenyl acetate,tetrahydromyrcenol, terpineol, terpinyl acetate, nopol, nopyl acetate,2-phenyl-ethanol, 2-phenylethyl acetate, benzyl alcohol, benzyl acetate,benzyl salicylate, styrallyl acetate, benzyl benzoate, amyl salicylate,dimethylbenzyl-carbinol, trichloromethylphenyl-carbinyl acetate,p-tert-butylcyclohexyl acetate, isononyl acetate, vetiveryl acetate,vetiverol, α-hexylcinnamaldehyde,2-methyl-3-(p-tert-butylphenyl)propanal,2-methyl-3-(p-isopropylphenyl)propanal, 2-(p-tert-butylphenyl)-propanal,2,4-dimethyl-cyclohex-3-enyl-carboxaldehyde, tricyclodecenyl acetate,tricyclodecenyl propionate,4-(4-hydroxy-4-methylpentyl)-3-cyclohexenecarboxaldehyde,4-(4-methyl-3-pentenyl)-3-cyclohexenecarboxaldehyde,4-acetoxy-3-pentyl-tetrahydropyran,3-carboxymethyl-2-pentylcyclopentane, 2-n-heptylcyclopentanone,3-methyl-2-pentyl-2-cyclopentenone, n-decanal, n-dodecanal, 9-decenol-1,phenoxyethyl isobutyrate, phenylacetaldehyde dimethylacetal,phenylacetaldehyde diethylacetal, geranyl nitrile, citronellyl nitrile,cedryl acetate, 3-isocamphylcyclohexanol, cedryl methyl ether,isolongifolanone, aubepine nitrile, aubepine, heliotropin, coumarin,eugenol, vanillin, diphenyl oxide, hydroxycitronellal, ionones,methylionones, isomethylionones, irones, cis-3-hexenol and estersthereof, indan musks, tetralin musks, isochroman musks, macrocyclicketones, macrolactone musks, ethylene brassylate.

Solvents which can be used for perfumes which contain an amide accordingto the invention are, for example: ethanol, isopropanol,diethyleneglycol monoethyl ether, dipropylene glycol, diethyl phthalate,triethyl citrate, isopropyl myristate, etc.

The quantities in which one or more amides according to the inventioncan be used in perfumes or in products to be perfumed may vary withinwide limits and depend, inter alia, on the nature of the product, on thenature and the quantity of the other components of the perfume in whichthe amide is used and on the olfactive effect desired. It is thereforeonly possible to specify wide limits, which, however, provide sufficientinformation for the specialist in the art to be able to use an amideaccording to the invention for his specific purpose. Typically, aperfume comprises one or more amides in accordance with the invention inan olfactively effective amount. In perfumes an amount of 0.01% byweight or more of an amide according to the invention will generallyhave a clearly perceptible olfactive effect. Preferably the amount is0.1 to 80% by weight, more preferably at least 1%. The amount of theamide according to the invention present in products will generally beat least 10 ppm by weight, preferably at least 100 ppm, more preferablyat least 1000 ppm. However, levels of up to about 20% by weight may beused in particular cases, depending on the product to be perfumed.

In a further aspect the invention provides a perfume comprising one ormore amides of the invention in an olfactively effective amount.

The invention also covers a perfumed product comprising one or moreamides of the invention.

Amides in accordance with the invention may be readily synthesised,potentially cheaply, from the corresponding amine by reaction with anappropriate acid chloride or anhydride.

The invention will be further described, by way of illustration, in thefollowing Examples.

EXAMPLE 1

This example describes synthesis of2-ethyl-N-methyl-N-(3-methylphenyl)butanamide (compound 1) by thefollowing route:

Preliminary step A is only used when N-methyl-m-toluamide is notavailable, and is as described in Org. Synth. Coll. Vol. IV (1963),p420.

Step B (via the acid chloride) uses the following materials:

N-methyl-m-toluamide  121 g,  1.0 mol Ethylbutyryl chloride  152 ml, 1.1mol Triethylamide  167 ml, 1.2 mol Dichloromethane 1000 ml

The acid chloride was added to a stirred solution of theN-methyl-m-toluamide in dichloromethane whilst keeping the temperaturebelow 20° C. Once the addition was complete the reaction was left towarm up to room temperature and then poured into water (500 ml). Theorganic and aqueous layers were thoroughly mixed by shaking and onceseparated the aqueous layer was discarded. The organic phase was washedwith a further 500 ml portion of water, and then dried with magnesiumsulphate.

The solvent (and residual triethylamine) was removed under vacuum andthe crude product (200 g) that remained was distilled under reducedpressure (101° C.@0.25 mmHg) to yield a colourless liquid. The productwas stirred with activated charcoal for 24 hours followed by filtrationthrough celite.

After the charcoal treatment 162 g (74%) of material with the desiredodour quality (tropical fruit, cassis) was obtained.

¹H NMR (400 MHz, CDCl₃, Ref TMS at 0.0 ppm) 7.25 (1H), 7.10 (1H), 6.91(2H), 3.25 (3H), 2.35 (3H), 2.15 (1H), 1.58 (2H), 1.31 (2H), 0.75 (6H)¹³C NMR (100 MHz, CDCl₃, Ref. CDCl₃ at 77.0 ppm) 176.2, 144.2, 139.7,129.4, 128.5, 128.4, 124.9, 45.0, 37.4, 26.1, 21.3, 12.2

EXAMPLE 2

A perfume in accordance with the invention was prepared by mixingtogether the following materials.

% by weight Aquanal (Q) 1 Bangalol (Q) 5 Bergamot AB 1589 5 Cervolide(Q) 25 Citronellol Pure 0.5 Dipropylene Glycol 20.5 Ethyl acetoacetate 1Geranium Bourbon Pure 0.5 Ionone (Q) 1 Ligustral (Q) 10% solution in DPG1.5 Magnolan (H & R) 5 Tropical Fruit Amide (compound 1) 1 Maltol 10%solution in DPG 0.5 Methyl dihydrojasmonate high Cis 70 (Q) 12 Methylpamplemousse (G) 0.5 Nerolidol 5 Orange Brazil Pure 2 Orange Flower AB2169 0.5 Peomosa (IFF) 2.5 Rhubofix (F) 10% solution in DPG 2 Rose OxideRacemic 1% solution in DPG 1 Silvanone (Q) 5 Veloutone (F) 10% solutionin DPG 2 DPG = Dipropylene glycol Q, H & R, F, IFF and G are allabbreviations for company names (Q = Quest, H & R = Haarman & Reimer, F= Firmenich, IFF = International Flavours and Fragrances, G = Givaudan)and the associated materials are identified by Trade Marks.

1. A compound having the structure

wherein R=methyl, ethyl or propyl, R₁=methyl or H, R₂ =methyl, ethyl orpropyl, R₃=methyl or H, R₄=methyl or ethyl, R₅═H or methyl, and where R₃and R₅ are not both H, excludingN-ethyl-2-methyl-N-(3-methylphenyl)propanamide, said compound beingcharacterized by its fruity cassis odor.
 2. A compound according toclaim 1, having the structure


3. A compound according to claim 1, having the structure


4. A perfume comprising one or more compounds in accordance with claim1, in an olfactively effective amount.
 5. A perfume according to claim4, wherein the compound is present in an amount of at least 0.01% byweight.
 6. A perfume according to claim 5, wherein the compound ispresent in an amount in the range 0.1 to 80% by weight.
 7. A perfumedproduct comprising one or more compounds according to claim 1 or aperfume according to claim 4.